Oil-in-water emulsions have been widely used as flavor delivery systems in the food industry, especially in the area of soft-drinks and beverages. However, their limited thermodynamic stability, which means that they always tend to separate into their two original liquid phases on standing, represents the biggest drawback in application and has the consequence that such delivery systems always need to be improved. A solution provided by the prior art consists in using bulk thickeners such as for instance vegetable gums or seaweed extracts in the continuous phase of the emulsion. However, this alternative always increases the viscosity of the emulsified system which may be a limiting factor for a further use of the emulsions in such applications.
The prior art also reports the existence of many oil-in-water systems suitable for the preparation of dairy or dairy-like products. In these systems, the discontinuous phase generally consists of both oil and a fat. The latter include either animal oils or fats, such as milk fat or butter oil and vegetable fats and oils, which are known per se in the food industry. Most often, the aim pursued in preparing such emulsions is to provide products which, as for the dairy-like products to be prepared therefrom, show the greatest possible similarity with natural milk. These systems, together with milk, wholly, or partly skimmed or reconstituted milk, can be processed to dairy or dairy-like products. In these emulsions, a whey protein ingredient is used as it is known to have good emulsifying properties.
Furthermore, it is reported in an article from Einhorn-Stoll et al. that polysaccharides play as well an important role in emulsion stabilization. More particularly, the authors report in two articles, namely in Nahrung 40 (1996), Nr. 2, p. 60-67 and Nahrung 42 (1998) Nr. 314, p. 248 and 249, a system in the form of a sunflower oil-in-water emulsion. They study the influence of the addition of high molecular weight polysaccharides, namely HM pectin, low methoxyl (LM) pectin and amidated pectin in whey protein emulsions. Einhorn-Stoll et al. conclude that, due to the formation of complexes between the protein and the free carboxylic groups of the pectin, LM pectin (having a low degree of esterification and therefore many free carboxylic groups) is more adapted than HM pectin for stabilizing these emulsions. In other words, the content of this document guides towards the use of LM pectin for stabilizing whey protein emulsions.
However, the experimental results provided by the above-mentioned articles are, as stated by the authors themselves, very different and inhomogeneous. Besides, the emulsions disclosed therein have a dispersed phase consisting essentially of a vegetable oil.
Now, the system of the present invention is different in several points from that disclosed in this prior art. In fact, the invention provides a delivery system for a lipophilic, optionally volatile substance, typically a flavor, which needs to be stabilized in a system such as an emulsion in order to be effectively released in a final application. Therefore, contrary to the emulsions described in the above-mentioned prior art, the dispersed phase of the system of the invention comprises, together with the oil, a substance capable of modifying the organoleptic properties of a composition to which it is added, typically a flavor ingredient or composition. Furthermore, the oil on which is based the dispersed phase is not from a vegetable origin, but from an animal origin.
Therefore, given the composition differences existing between the system object of the present invention and that disclosed in the prior art, in particular by Einhorn-Stoll et al., it was basically not very likely that the results reported by this document could be used in a system such as that of the invention. However, even if one had tried to use the results taught by the mentioned articles, this person would have been guided to use LM pectin as an emulsifier of a system containing whey protein.